The patient came to the clinic 12-February-2022 complaining of difficult walking with LBP for 8 years. Using crutches for 4 years. MRI done 07-February-2022 showing bulge C6-7 with severe stenosis L4-5. The patient is insulin-dependent diabetic for 9 years and hypertensive for 1 year and undergoing dialysis for 1 week 3 times a week. He has cough for several years. Echocardiogram showing mild pericardial effusion. EMG done 07-February-2022 reporting severe senso-motor polyneuropathy affecting both upper and lower limbs.

On examination, the patient now is limping with scoliotic stance. Using crutches for 4 years. The interossii muscles both hands are atrophied with weak grip both hands 4/5 and extensors 2/5. The proximal muscles of upper limbs are 5/5. SLRS was 60 degree right side due to weakness. There is weak dorsiflexion right foot 4/5 and both quadriceps 4/5. There is hypalgesia below right L1 and the left foot above the ankle.

The patient was sent for investigations and MRI of the brain requested, showing only polyp left maxillary sinus and lumbar spine done 02-February-2022 showing severe lumbar canal stenosis L4-5 with bulge D7-8.

The patient was admitted first at 26-February-2022 and he was Covid positive for what he was advised to come back after he recover a negative result.

Decompressive laminectomy L4-5 with foraminotomy both L5 roots. Inspection of the annulus fibrosis was uneventful. Using MultiGen, bipolar stimulation of the left and right L5 roots was not responding. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the right L5 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar stimulation of the right L5 root was not responding. Bipolar stimulation of the muscles with 10 Volts was not responding. It seems that the patient did not recover from induction muscle relaxant given at the start of surgery. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. Smooth postoperative recovery. The power of the right foot improved. He was sent to the ward.

Too early now.

The stenosis when severe, decompression have better outcome.

This is the 234th case using the BPRF mode with MultiGen. This procedure regained routine acceptance.  It became a usual part of the spine and peripheral nerves surgery. Click here for reference.

It still unclear to evaluate the differences of pre and post application motor responses. The only sure thing that it tells that the electrodes did not migrate during the procedure and the nerve is functioning properly. Here it was impossible to evaluate pre and post application due to renal failure with delayed recover form muscle relaxant induction.

With accumulation of data, it became clear that the irritated nerve with aberrant currents running in the C fibers up, not only causing no change or elevation of the required voltage to achieve motor response, but they could cause the preoperative weakness. Ablation of such currents results in facilitation of the motor response and improvement of function with disappearance of pain.

It is unclear why the roots have several motor response with different patients, despite the fact that the neurological status is the same and the anesthesia protocol also the same.

It could be that the nerve is recovering minute by minute after decompression and this can explain why the motor conductivity is improving after the BPRF application, which require 4 minute session in most cases.

After the 172d case, the elevation of motor stimulation above 5 V was abandoned to avoid delayed dural tear with subsequent CSF leak, which take place at the contact at the lower electrode shaft with the dura below the level of the axilla.

With patient with renal failure, administration of induction muscle relaxant will prevent motor evaluation of the nerves, but it is still logical to apply BPRF to the involved root.